Your dog got a taste for blood now, muzzle at all times or it will be a bloodbath every time you go for a walk. Moles are known to be very vindictive they will tunnel under your house and bring it all tumbling down. Mate you are flat out f*cked

Dr P.... V funny!
I would suggest that the mole didn't 'suffer' as it was dead in seconds by the sound of it. It's not like you allowed you dog to toss it around for ages and then tried to make slippers out of it before it was dead!
It happened, you feel bad, lesson learned, get over it. And don't feel bad any more please!